emalloc / erealloc again with APC

I'm getting emalloc / erealloc errors in stderr.log which cause one of my vhosts not to work (I always get a 503 error). The single vhost which isn't working is serving a MediaWiki installation. The other (working) vhosts serve simple php-sites.

I tried setting these limits to a very high number (memory about 160MB) instead of 0, but this didn't change anything. I restarted the server several times. If you need any more information, just tell me.

Setting both memory limits to 0 or alternatively to soft: 200M, hard: 240M "fixes" the error, setting it to a low value like 20M brings a 503 error again! Now, is this the real solution to disable memory limits or is it still a bug but disabling the limit just hides it?

Edit: I encountered the error again during a Wordpress installation with memory limits soft: 200M, hard: 240M.
Edit 2: Sorry, this may have happened because of other memory limits set in this special VHost template.. (Edit 3, yes, it was because of these limits. Removed all memory limits but soft: 200M, hard: 240M in Server -> Security -> CGI Resources -> Memory soft/hard settings and it's still running fine)

in my stderr.log when I have APC enabled.
This happens when I use a self-created PHP script which loads a 8MB serialized (on disk) object and plays with it. Didn't try to see what exactly in my script made it spit this error; I would guess it errors out when loading the object.
The only way I found to make it work is to disable apc in php.ini

I tried using either 0 or high values (300M/450M) as memory soft/hard limits in both Server > Security > CGI Resource and VHost > External Apps > LSAPI App, but it didn't help al all.

You can contact me via AIM at handle: "litespeedtech". Please note I am on the US West Coast PST time. I will be willing to talk to you and access your machines to find out exactly what os/app parameter is causing this.

We have found that the use of APC can artificiallly accelerate PHP's memory usage/requirement for certian scripts/operations, i.e. deserialize() large serialized packets. Most likely a problem within APC.

We recommend that users of APC/PHP that encounter the emalloc() errors to increase memory ceiling for external processes via LiteSpeed admin: